Semiconductor devices including compounds such as GaN, AlGaN, and the like have many advantages of wide and easily adjustable bandgap energy and the like such that the semiconductor devices may be variously used as light-emitting devices, light-receiving devices, various diodes, and the like.
In particular, a light-emitting device such as a light-emitting diode (LED) or a laser diode using a compound semiconductor material of a Group III-V or II-VI compound semiconductor can implement various color light such as red light, green light, blue light, and ultraviolet rays with development of a thin film growth technique and an element material, can also implement white light with high efficiency using a fluorescent material or combining colors, and has advantages of low power consumption, a semi-permanent lifetime, a fast response speed, safety, and environmental friendliness as compared to conventional light sources such as fluorescent lamps and incandescent lamps.
In addition, when a light-receiving device such as a photodetector or a solar cell is manufactured using a Group III-V or II-VI compound semiconductor material, due to development of an element material, the light-receiving device absorbs light of various wavelength regions to generate a photoelectric current such that light in various wavelength regions from gamma rays to a radio wavelength range can be detected. Further, such a light-receiving device has advantages of a fast response speed, safety, environmental friendliness, and easy control of device materials such that the light-receiving device can also be easily used as various sensors for power control, a microwave circuit, a communication module, or detection of a gas or ultraviolet (UV) rays.
Accordingly, applications of the semiconductor device have expanded to being applied as a transmission module of an optical communication device, an LED backlight replacing a cold cathode fluorescent lamp (CCFL) which configures a backlight of a liquid crystal display (LCD) device, a white LED lighting device capable of replacing a fluorescent lamp or an incandescent lamp, a headlight of a vehicle, traffic lights, a sensor for detecting a gas or fire, and the like. Further, applications of the semiconductor device can be expanded as being applied to a high frequency application circuit, other power control device, and a communication module.
In the conventional semiconductor device, an electric field is strongly formed at an edge of an electrode such that there is a problem in that the semiconductor device can be damaged.